Considering the difference in moonrise times between regions of the Kingdom

Question:
In… Is it permissible for someone in the Saudi state, for example in Najran or the Eastern Province, to say, “I do not fast except based on the moon sighting in this location”? And what is the distance at which moonrise times differ?

Answer:
The distance at which moonrise times differ is known by the astronomers. However, everyone in Saudi Arabia is bound to follow the same ruling, because they are under one Imam. It is not permissible for them to have different rulings, even though they are in one country. This was the case when there were no means of communication in the early days, when there were no means to convey the sighting of the crescent, such as the Frizah or the Ruwaib, or whatever. At that time, it was only by means of mounts. Yes, they could not fast based on the sighting in other regions because the means of communication were cut off. But now, when means of conveying the news of the crescent have emerged, it is obligatory for all the people of the Kingdom to fast, because they are under one command, under one Imam, and the news has reached them. Moreover, it is the general rule that the moonrise time does not differ for them, as the Kingdom is geographically close.